Reserve Minimum Coverage

I'm going to the opera in Augsburg. I just don't know when. I need to trade one more day to make sure I get to the city on time for the opera and then have a few more to play in Munich. But if scheduling rolls my day, then I get to play in Munich for a few days and then see the opera. I'd like to plan where I'm staying and book the hostels but that's not looking like a possibility when I don't know where I'll be until I get there... And the reason why I can't trade my day? Reserve minimum coverage.